1. Field of the Invention
The present invention relates to a method and apparatus for correcting ultrasound images by using an interest index map.
2. Description of the Related Art
An ultrasound diagnosis apparatus delivers an ultrasound signal from a body surface of a target object to a predetermined part in the body, and then obtains an image of tomography or hematocele of a soft tissue by using information of the ultrasound signal reflected from a tissue in the body.
The ultrasound diagnosis apparatus is advantageous in that it is small, is inexpensive, and displays in real-time. Also, the ultrasound diagnosis apparatus is not harmful such as radioactivity and thus is safe, so that it is widely used together with an X-ray diagnosis apparatus, a computerized tomography (CT) scanner, a magnetic resonance image (MRI) apparatus, a nuclear medicine diagnosis apparatus, and the like.
In general, an output (a transmission voltage, a pressure, and energy) of the ultrasound diagnosis apparatus is limited by and is decided according to an international reference (e.g., a mechanical index (MI)). Here, the MI is an index of quantification of mechanical affects by ultrasound with respect to a human body.
Another example of the quantification of mechanical affects by ultrasound with respect to a human body is a thermal index (TI). According to a common level, international permission levels of the MI and the TI are less than 1.9 and 6.0, respectively.
The ultrasound diagnosis apparatus further precisely diagnoses a target object by increasing a transmission voltage of an ultrasound signal which is output from a pulser. In this regard, as the transmission voltage is increased, a sensitivity of an image is improved but the MI or an acoustic pressure (a pressure generated by ultrasound that passes through a medium) is increased.
Also, when an ultrasound signal output from the ultrasound diagnosis apparatus passes through a medium such as a human body, interest indexes such as the MI, the acoustic pressure, the TI, and the like may not have regular dispersion in one frame, according to a focus forming method or an interest depth of an ultrasound beam.
That is, ultrasound images based on a received ultrasound echo signal do not have a uniform brightness or quality of some of the ultrasound images may deteriorate.